Drawing on the expertise of champion ultra runner Scott Jurek, the Ultimate Direction SJ Ultra Vest effectively balances weight and performance in providing at the ready hydration for long distance running or racing. Weighing just 7.5 ounces without bottles, the vest carries everything you need for a day on the trail while providing freedom of movement that lets you concentrate on the trail ahead.The SJ Ultra Vest is constructed of innovative cuben fiber fabric. Though extremely lightweight, cuben fiber has an incredible strength to weight ratio that enables the vest to carry two full water bottles, a full hydration bladder sold separately and ample storage space despite weighing less than half a pound. Hex mesh fabric is used on strapping and strategically throughout the pack body for a comfortable fit and breathable performance. Dual sternum straps with sliding adjustability help you to dial in fit. To further ensure a proper fit, the SJ Ultra Vest is available in Small 25 31 chest, Medium 31 38 and Large 38 43 sizes. NOTE: When full of gear, the vest will fit smaller.There are two stacked, zippered main compartments on the SJ Ultra Vest. The one closest to the body can safely stow a hydration bladder sold separately and cuben fiber bellows expand to accommodate a full load of gear. The upper pocket is constructed of power mesh. On the face of the pack, a zig zag bungee attachment system is a perfect spot for securing gloves, discarded layers or other items you want to keep readily accessible. Two large, zippered mesh lat pockets gobble up a ton of gear and have stash space wedged in behind them. On the chest portion of the harness there are twin water bottle pockets which conveniently secure two 20 oz Bottles with Kicker Valves. These iconic bottles provide efficient, leakproof performance and have long been the go to option for trail runners.Based on Scott's countless hours spent in the backcountry, intuitively placed pockets abound on the front portion of the pack, serving as ideal stow options for gels, electrolytes, cell phones and other essentials. Cinch down features on the water bottle pockets also allow them to safely stash cameras and other electronics. Other nice touches include an integrated safety whistle, trekking pole loops and an ice axe loop.Drawing on the expertise of champion ultra runner Scott Jurek, the Ultimate Direction SJ Ultra Vest effectively balances weight and performance in providing at the ready hydration for long distance running or racing. Two 20 oz sport bottles included. Large Gunmetal, Small Gunmetal, 00458313 L, 00458313 S